1. Field of the Invention
The present invention provides a fluid-confining apparatus and method of operating it, and especially a fluid-confining apparatus that can be applied to a plating process, a cleaning process or a polishing process.
2. Description of the Prior Art
Technologies used for depositing a metal material layer include a physical vapor deposition, a chemical vapor deposition, an electroless plating process, an electro-chemical deposition, and so forth at present. With advantages of low cost and high throughput, electro chemical plating (ECP) technology is widely used in the semiconductor industry. During the process of electro chemical plating, the uniformity of the surface of the formed layer is affected by factors such as a component of an electrolyte fluid, temperature, current density, and a cleanness of the deposited surface.
Please refer to FIG. 1 through FIG. 3. FIG. 1, FIG. 2 and FIG. 3 are schematic diagrams illustrating a prior art electro chemical plating process. As shown in FIG. 1, a wafer 10 and a plating apparatus 20 are first provided. The plating apparatus 20 includes an electrolytic tank 12, an electrolyte fluid 22, an anode system 14, a cathode electrode 16 and a fixing component 18. The electrolytic tank 12 is applied for storing the electrolyte fluid 22, and the main component of the electrolyte fluid 22 is metal ions. The anode system 14 includes an anode chamber 30, an anode electrode 24, a filter membrane 26, a diffuser membrane 28, and an electrolyte fluid supplying tube 32.
The wafer 10 is positioned between the cathode electrode 16 and the fixing component 18 so that the wafer 10 is clamped tightly by both the cathode electrode 16 and the fixing component 18. Next, as shown in FIG. 2, the wafer 10 is a little bit inclined so that the wafer 10 and the liquid surface of the electrolyte fluid 22 have a small angle. The wafer 10 is dipped into the electrolyte fluid 22 slowly so that bubbles will not attach to the surface of the wafer 10. Afterward, as shown in FIG. 3, the wafer 10 is electrically connected the cathode electrode 16 for being plated. For improving the uniformity of the deposited thin film, the cathode electrode 16 normally spins so as to ensure that the wafer 10 can continually contact a fresh electrolyte fluid during the electro chemical deposition process. When an external voltage or current is applied to the plating apparatus 20, a circuit including the anode system 14, the electrolyte fluid 22, the cathode electrode 16 will conduct, and a reduction reaction occurs around the cathode electrode 16 so that the metal material is deposited on the wafer 10.
The prior art electro chemical plating process not only forms the metal material on the front side of the wafer 10, but also forms the metal material on the edge bevel of the wafer 10. However, the metal material attached to the edge bevel is actually unnecessary for the products. Pealing of the remaining metal material frequently occurs in subsequent processes due to thermal stress or other reasons, leading to the cracking of the metal material. Flakes and particles of the metal material caused by the cracking frequently fall on the lower wafers and contaminate top surfaces of the semiconductor wafers positioned under the semiconductor wafer 10 during either a chemical vapor deposition (CVD) process or the transportation of the semiconductor wafers. Thus, the performance of the products is greatly affected.
In order to avoid the above-mentioned problem, an additional removing process, an additional cleaning process and an additional drying process should be carried out to remove the metal material attached to the edge bevel after the prior art electro chemical plating process. It will not only increase the process time and the process cost, but also increases the complexity of the process. As a result, the yield of products is decreased. Referring to the electrolyte fluid 22, since the whole anode system 14, the whole wafer 10 and the whole electrode 16 should be bathed in the electrolyte fluid 22, and the wafer 10 has to be inclined when the wafer 10 is going into the electrolyte fluid 22, a huge electrolytic tank 12 and a great deal of the electrolyte fluid 22 are required for the prior art electro chemical plating process. After a period of the electro chemical plating process, the process should be paused for exchanging the electrolyte fluid 22. The old electrolyte fluid 22 should be poured out, and then the new electrolyte fluid 22 is infused into the electrolytic tank 12. Accordingly, the exchange of the electrolyte fluid 22 takes a long time and therefore reduces the output.
On the other hand, in order to perform the prior art electro chemical plating process, a single wafer 10 is first disposed between the cathode electrode 16 and the fixing component 18 by a robot arm, and is disposed into the electrolyte fluid 22 at an angle. Thereafter, the plating apparatus 20 is opened to perform the plating reaction. Next, the wafer 10 is removed from the electrolytic tank 12, and undergoes the subsequent processes, such as a cleaning process and a drying process. According to the operational limitation of the prior art plating apparatus 20, the electro chemical plating process cannot handle a great deal of wafer 10 in batch, and seriously affects the output of products. Furthermore, it is difficult for the prior art plating apparatus 20 to perform an in-situ measurement on the wafer 10. As a result, the electro chemical plating process cannot be accurately and quickly controlled, and an additional time is required for the measurement.